Electric shower issue

[Ivanm]

hi there
i recently had to change the hand held part of my shower because the shower holder had broken, to do this i had to dismantel the slider rail etc, now when i go to put on the shower it seems to take longer for the shower to work, prior to changing the broken part i would put my hand in the shower to turn it on and i would instantly get hot water, now it seems to take longer to start.
thankyou for your advice
Ivan